1. Field of the Invention
The present invention relates to a circuit arrangement for automatic distortion correction of a signal which has been transmitted over a line having low-pass filter characteristics and which is fed to a distortion corrector having a controllable high-pass filter and a controllable-gain amplifer. As an example, the line can be a two-wire circuit of a local cable.
2. Description of the Prior Art
As is well known in the art, the level of a signal is lowered all the more after transmission by way of a line, with respect to the length of the line. At the same time, all frequency components and, particularly the high-frequency components, of the signal are attenuated all the more, the longer the line. Therefore, the low-pass filter behavior of the line is all the more pronounced with increasing line length. As is known in the art, a distortion-corrected signal is desired whose level and whose frequency characteristic is constant and independent of the length of the line.
For automatic distortion correction of a signal, as is known in the art, the signal to be corrected can be transmitted by way of a controllable high-pass filter and by way of a controllable-gain amplifier, whereby, as a function of the output signal of the controlled-gain amplifier, a control voltage is derived with which both the high-pass behavior of the high-pass filter, as well as the amplification of the controllable-gain amplifier, can be regulated in such a manner that a distortion-corrected signal is delivered at the output of the control-gain amplifier. Circuit arrangements known in the art which effect such an automatic distortion correction of the signal require a relatively large technical expense and a large expense with respect to time in order to match the various control loops of the high-pass filter and of the controlled-gain amplifier to one another and adapt the same to the low-pass filter characteristic of the line.